CN115405643B

CN115405643B - Electromechanical brake and vehicle provided with an electromechanical brake

Info

Publication number: CN115405643B
Application number: CN202210957139.XA
Authority: CN
Inventors: 宋浚圭; 孙平国; 金振锡; 林佑澈; 郑大俊
Original assignee: Mando Corp
Current assignee: HL Mando Corp
Priority date: 2021-08-11
Filing date: 2022-08-10
Publication date: 2023-04-14
Anticipated expiration: 2042-08-10
Also published as: DE102022120333A1; US11841057B2; US20230175565A1; DE102022120333B4; US11629766B2; CN115405643A; US20230062142A1; KR102401765B1

Abstract

The invention provides an electromechanical brake and a vehicle provided with the electromechanical brake. An electromechanical brake according to an aspect of the present invention includes a pair of brake pads provided on both sides of a brake disc, wherein the electromechanical brake includes: the brake device includes a motor that supplies a rotational driving force, a rotary screw that rotates about a second rotation axis parallel to a first rotation axis of the motor, a power transmission unit that transmits the rotational driving force of the motor to the rotary screw, and a piston that is coupled to the rotary screw so as to be movable forward and backward so that the brake pads press the brake disc.

Description

Electromechanical brake and vehicle provided with an electromechanical brake

Technical Field

The present invention relates to an electromechanical brake and a vehicle including the same, and more particularly, to an electromechanical brake that provides a pressing force using a rotational driving force of an electric motor and a vehicle including the same.

Background

Generally, a braking device is a device for stopping a vehicle so as not to move during braking or parking, and for holding a tire of the vehicle against rotation.

Recently, electro-Mechanical Brake (EMB) systems for electronically controlling the actuation of the brakes are being developed. Such an electromechanical brake can be operated not only manually by a driver but also automatically in the case of a vehicle to which an automatic driving system is applied, and thus is very convenient and can realize the upgrading of the vehicle.

In the case of an electromechanical brake that provides a braking force to a vehicle by pressing a brake disc, the rotation driving force of a motor is transmitted to a screw and nut structure that is screwed together, and the brake disc is pressed by the screw or nut, thereby controlling the rotation of the brake disc.

In this case, since the rotational driving force of the motor cannot be directly transmitted to the screw or the nut, and the power is transmitted from the motor to the screw or the nut by using a plurality of gears for speed reduction, there has been a problem that the load due to the rotational force is large and the durability is deteriorated because the gears for transmitting the power are aligned in a row in the conventional electromechanical brake.

On the other hand, conventionally, driving force is supplied only to a parking brake for parking by using an electronically controllable electric motor, and driving force is supplied to a service brake for service control by a commonly used hydraulic pressure. Thus, when the parking brake and the service brake are separately provided, there is a problem in that not only the occupied space inside the vehicle increases, but also the overall weight of the vehicle increases.

Thus, the demand for electromechanical brakes is increasing as follows: which can be electronically controlled while performing the functions of a parking brake and a service brake with one device, thereby removing hydraulic lines and effectively using the inner space of the vehicle.

On the other hand, in a vehicle such as a large truck requiring a large braking force, a plurality of pistons (two pistons are generally applied) are provided for performing a braking operation.

However, when a plurality of pistons are provided and a driving force is received from a single motor, a load is unevenly transmitted to the plurality of pistons according to an initial position where the pistons are uneven, so that there are problems in that one-side wear of brake pads, one-side wear of gears, overload of the motor, etc. due to asymmetry occur. This causes a problem of deterioration in braking performance.

In order to solve this problem, the same number of motors as the pistons are provided so as to transmit power to each of the plurality of pistons, however, there is a problem in that not only weight and cost are increased, but also an installation space is narrow and difficult to apply.

[ Prior art documents ]

[ patent document ]

Korean patent laid-open publication No. 10-2021-0042587 (Caliper brake)

Disclosure of Invention

Problems to be solved by the invention

In order to solve the above problems, an object of the present invention is to provide an electromechanical brake capable of electronically controlling a braking force.

An object of the present invention is to provide an electromechanical brake that improves durability of gears by reducing loads applied to a plurality of gears for transmitting a driving force of a motor.

It is an object of the present invention to provide an electromechanical brake that is capable of providing service brake and parking brake functions electronically without hydraulic lines.

The invention aims to provide an electromechanical brake, which is relatively small in damage and small in backlash (backlash) of a rotating screw in a braking environment in which dust and foreign matters are easily generated.

The invention aims to provide an electromechanical brake which can provide enough braking force even when a brake sheet is worn.

The invention aims to provide an electromechanical brake which can maintain the braking force of the brake in the parking condition.

An electromechanical brake is provided which increases braking force by applying a stronger load to a brake pad.

The problems of the present invention are not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

Means for solving the problems

In order to solve the above-mentioned problems, an electromechanical brake according to an aspect of the present invention includes a pair of brake pads disposed on both sides of a brake disc, wherein the electromechanical brake includes: a motor that supplies a rotational driving force, a rotary screw that rotates about a second rotation axis parallel to a first rotation axis of the motor, a power transmission unit that transmits the rotational driving force of the motor to the rotary screw, and a piston that is coupled to the rotary screw so as to be movable forward and backward so that the brake pad presses the brake disc; the power transmission unit may include: a first gear coupled to the first rotation shaft of the motor, a second gear coupled to the second rotation shaft of the rotation screw, and a third gear engaged with the first gear and the second gear and rotating about a third rotation shaft disposed apart from a plane including the first rotation shaft and the second rotation shaft.

At this time, the electromechanical brake may further include a planetary gear structure, one side of which is coupled to a rear end of the rotary screw; the second gear may be coupled to the other side of the planetary gear structure.

At this time, the first gear, the second gear, and the third gear may be helical (helical) gears.

At this time, the electromechanical brake further includes a ball nut combined with the rotary screw, and the rotary screw includes: a first body coupled to the ball nut, and a second body formed behind the first body and coupled to the second gear; the piston is formed in a cup shape having an opening portion at a rear portion thereof, and the ball nut is inserted into the opening portion of the piston so that the piston can be pressed forward.

At this time, the electromechanical brake further includes a connection member formed to surround a front end portion of the ball nut so as to be pressed forward by the ball nut, and a first screw portion formed on an outer circumferential surface of the connection member; a second screw part screw-coupled with the first screw part may be formed at an inner circumferential surface of the piston.

In this case, an inclined surface is formed along a circumference of a front edge portion of the ball nut, and a support surface corresponding to the inclined surface is formed on a front inner circumferential surface of the connection member so as to be pressed by the inclined surface.

At this time, the rotary screw further includes a third body portion formed between the first body portion and the second body portion, the first body portion, the third body portion, and the second body portion being formed such that sizes of cross sections perpendicular to a length direction are sequentially reduced, and the electromechanical brake may further include: a support member disposed on an outer peripheral surface of the third body portion, a front surface of the support member being supported on a rear end edge portion of the first body portion, and an elastic member having one side coupled to the support member and the other side coupled to the ball nut so as to pull the ball nut toward the support member.

At this time, the electromechanical brake may further include a thrust bearing (thrust bearing) disposed rearward of the support member to support a load generated by an axial force of the rotary screw.

At this time, the electromechanical brake may further include a rotation prevention portion controlling the third gear to be rotatable only in one direction.

At this time, the rotation preventing part includes a latch inserted into a first space formed at one side of the third gear, the third gear may be in a locked state rotatable only in one direction when the latch is inserted into the first space, and the third gear may be in an unlocked state rotatable in both directions when the latch is separated from the first space.

At this time, the latch is pivotably fixed, and the rotation preventing portion further includes: a plurality of protrusions formed continuously along a circumference of the third gear at one side of the third gear, and an actuator for controlling pivoting of the latch; a plurality of the first spaces may be formed between the plurality of protrusions.

At this time, a guide surface formed obliquely may be provided on one side of the plurality of protrusions in the circumferential direction of the third gear.

In this case, the pair of pistons may be provided symmetrically with respect to the center of the brake pad, and the pair of rotary screws may be provided symmetrically with respect to the center of the brake pad.

At this time, the electromechanical brake may further include a load adjusting member that is rotatably provided between the pair of rotary screws and the power transmission portion, and applies a uniform load to the pair of rotary screws by pressing the rotary screws toward the brake disk, the rotary screws generating a small load when the brake disk is pressed.

At this time, the load adjuster member may be formed to extend in length, and both ends of the load adjuster member may be formed to be curved surfaces on the pair of the rotation screws.

At this time, the electromechanical brake further includes: a ball nut coupled to the rotary screw; the rotary screw includes: a first body part coupled to the ball nut, a second body part formed at a rear of the first body part and coupled to the second gear, and a third body part formed between the first body part and the second body part; the first body portion, the third body portion, and the second body portion are formed such that the size of a cross section perpendicular to the length direction is sequentially reduced, and the electromechanical brake further includes: a support member disposed on an outer peripheral surface of the third main body portion with a front surface thereof supported on a rear end edge portion of the first main body portion, and a thrust bearing disposed rearward of the support member to support a load generated by an axial force of the rotary screw; the load adjusting member may press a rear side of the thrust bearing.

As an electromechanical brake according to an aspect of the present invention, in an electromechanical brake provided at a wheel, a rotation speed of the wheel is controlled by pressing the brake disc with the brake pad while maintaining the unlocked state in a vehicle running state, and the locked state may be maintained while pressing the brake disc with the brake pad in the vehicle stopped state.

Effects of the invention

According to the electromechanical brake of an embodiment of the present invention, the braking force can be applied to the vehicle by pressing the brake disk with the driving force of the electric motor.

According to the electromechanical brake of an embodiment of the present invention, the three gears are arranged in a specific arrangement so as to transmit the driving force of the motor, thereby being capable of improving durability by reducing the load applied to the plurality of gears.

The electromechanical brake according to an embodiment of the present invention is capable of electronically providing service brake and parking brake functions without hydraulic lines.

In the electromechanical brake according to an embodiment of the present invention, the ball nut is provided, so that not only is relatively less damaged, but also the backlash of the rotating screw is small in a brake environment where dust and foreign substances are likely to occur.

In the electromechanical brake according to an embodiment of the present invention, the connecting member is provided so as to be able to provide sufficient braking force even if the brake pad is worn.

According to the electromechanical brake of an embodiment of the present invention, the braking force of the brake can be maintained in the parking state.

According to the electromechanical brake of an embodiment of the present invention, a uniform load can be applied to a plurality of pistons by one motor.

It is to be understood that the effects of the present invention are not limited to the above-described effects, and include all effects that can be inferred from the configuration of the present invention described in the specification or claims of the present invention.

Drawings

FIG. 1 is a perspective view of an electromechanical brake in accordance with an embodiment of the present invention.

Fig. 2 is an exploded perspective view of an electromechanical brake according to an embodiment of the present invention.

Fig. 3 is a length-wise sectional view of a rotary screw and a piston of the electromechanical brake according to an embodiment of the present invention.

Fig. 4 is an enlarged view of a portion a of fig. 3.

Fig. 5 is an enlarged view of a portion B of fig. 3.

Fig. 6 is an enlarged view of a power transmission portion of the electromechanical brake according to an embodiment of the present invention.

Fig. 7 is an enlarged view of a rotation preventing portion of an electromechanical brake according to an embodiment of the present invention.

Fig. 8 is a diagram illustrating a braking state of the electromechanical brake according to an embodiment of the present invention.

Fig. 9 is a diagram illustrating a driving state of an electromechanical brake according to an embodiment of the present invention.

Fig. 10 is a length-wise sectional view of a pair of a rotary screw and a piston of an electromechanical brake according to another embodiment of the present invention.

Fig. 11 is an enlarged view of a power transmitting portion of an electromechanical brake according to another embodiment of the present invention.

Fig. 12 is an enlarged view of a load adjuster of an electromechanical brake according to another embodiment of the present invention.

Fig. 13 is a diagram showing an operating state of a load adjuster of an electromechanical brake according to another embodiment of the present invention.

Description of the reference numerals:

1 electromechanical brake 360 third gear

20 brake disk 361 third rotation axis

30 first brake shoe 400 ball nut

40 second catch 421 inclined plane

50 casing 500 connecting member

60 carrier 520 protrusions

100 motor 521 bearing surface

200 rotating screw 540 first thread part

220 first body portion 600 piston

240 second body part 620 opening part

260 third body portion 640 second threaded portion

270 support member 700 rotation prevention part

280 elastic member 720 protrusion

290 thrust bearing 721 first space

300 power transmission part 722 guide surface

320 first gear 740 latch

321 first rotation axis 760 actuator

340 second gear 800 planetary gear structure

341 second rotating shaft 900 load adjusting member

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily practice the invention. The present invention may be embodied in various forms and is not limited to the embodiments described herein. Unless otherwise defined, terms used in the embodiments of the present invention may be interpreted as having meanings well known to those of ordinary skill in the art. Hereinafter, the expression "coupled" includes not only direct coupling but also indirect coupling through other configurations.

In order to clearly explain the present invention in the drawings, portions irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

In fig. 2 below, the description will be made with the X axis defined as the front, the Y axis defined as the left direction, and the Z axis defined as the upper direction. However, the forward direction does not mean that the brake disk should be disposed in front of the vehicle, but means a relative direction according to different directions.

The present invention relates to an electromechanical brake, and more particularly, to an electromechanical brake that controls braking force by pressing a brake disc with a rotary screw rotated by a rotational driving force of a motor.

In particular, the present invention provides an electromechanical brake that reduces a load applied to gears by a triangular configuration of a plurality of gears for transmitting a rotational driving force of a motor, thereby reducing wear or damage of the gears.

Further, the present invention provides an electromechanical brake capable of performing functions of a parking brake and a service brake using a driving force of an electric motor in one device without using a conventional hydraulic manner.

FIG. 1 is a perspective view of an electromechanical brake in accordance with an embodiment of the present invention. Fig. 2 is an exploded perspective view of an electromechanical brake according to an embodiment of the present invention. Fig. 3 is a length-wise sectional view of a rotary screw and a piston of an electro-mechanical brake according to an embodiment of the present invention. Fig. 4 is an enlarged view of a portion a of fig. 3. Fig. 5 is an enlarged view of a portion B of fig. 3.

An electromechanical brake 1 according to an embodiment of the present invention includes first and

second brake pads

30 and 40 as a pair of brake pads, a housing 50, a motor 100, and a carrier 60.

Referring to fig. 1 to 3, the first brake pad 30 and the second brake pad 40 are disposed with respective faces adjacent to a front surface and a rear surface of the brake disc 20, respectively.

As shown in fig. 1, the first brake pad 30 is coupled to a front side of the housing 50, and a carrier 60 disposed to be movable back and forth toward the brake disk 20 side is provided at the housing 50. At this time, the second brake pad 40 is bonded to the carrier 60 such that the second brake pad 40 can move forward and backward toward the brake disc 20 side together with the carrier 60.

As shown in fig. 2, an electric motor 100 is fixed inside the housing 50, and the electric motor 100 supplies power to move the second brake pad 40 or the first brake pad 30 and the second brake pad 40 toward the brake disc 20 side, thereby pressing the brake disc 20. At this time, the types of motors, such as direct current, brushless direct current (BLDC), and alternating current, are not limited as long as the motor 100 can provide a rotational driving force. As shown in fig. 2, the motor 100 is fixed to the housing 50 such that the main body faces forward, and a motor housing 102 may be coupled to the housing 50 to protect the main body of the motor 100.

As shown in fig. 2, the case 50 may be divided into a front case 52, a middle case 54, and a rear case 56. However, there is no limitation on the shape if a space is formed inside and the component can be fixed. The first brake disc 30 is fixed to the front housing 52, a piston 600, which will be described later, is coupled to the intermediate housing 54 so as to be movable forward and backward, and a power transmission unit 300, which will be described later, is fixed to the rear of the intermediate housing 54. The rear housing 56 is coupled to the rear of the middle housing 54 to protect the power transmission portion 300.

As shown in fig. 2, the electromechanical brake 1 according to an embodiment of the present invention includes a rotary screw 200, a piston 600, a power transmission part 300, and a ball nut 400 to press the second brake pad 40 using a rotational driving force of the motor 100.

As shown in fig. 2, the rotary screw 200 is formed in a cylindrical shape extending in length and is disposed inside the housing to be rotated by receiving a rotational driving force of the motor 100.

As shown in fig. 3, the rotary screw 200 includes a first body 220 formed at the front, a second body 240 formed at the rear, and a third body 260 formed between the first body 220 and the second body 240. The radii of the first, third and

second body portions

220, 260 and 240 decrease in order as they go rearward.

At this time, the rotary screw 200 is disposed inside the housing 50 such that a first rotary shaft 321, which is a rotary shaft of the motor 100, and a second rotary shaft 341, which is a rotary shaft on which the rotary screw 200 rotates, are disposed in parallel with each other.

The ball nut 400 is coupled to an outer circumferential surface of the rotary screw 200. At this time, as shown in fig. 3, the rotary screw 200 includes the first body portion 220 combined with the ball nut 400 and the second body portion 240 combined with the second gear 340 such that the rotary screw 200 receives the driving force from the motor 100.

On the other hand, as the rotary screw 200 is rotated by the rotational driving force of the motor 100, the ball nut 400 coupled to the rotary screw 200 moves forward or backward according to the rotational direction of the rotary screw 200. Such a ball screw nut joint is a known component, and thus a detailed description of the joint will be omitted.

In a brake system that provides a braking force by pressing a brake disc, dust is easily generated due to friction between a brake pad and the brake disc. Further, since the brake is generally disposed at the tire of the vehicle and disposed so as to be close to the road surface, dust or foreign matter easily rises when the tire moves on the road surface. At this time, as in the electromechanical brake 1 according to an embodiment of the present invention, the rotary screw 200 and the ball nut 400 are ball-screw-nut coupled, and therefore, even if dust enters between the rotary screw 200 and the ball nut 400, the rotary screw 200 and the ball nut 400 are less damaged, and thus the durability can be improved.

Further, the rotary screw 200 and the ball nut 400 perform the ball-screw-nut coupling, so that the electromechanical brake 1 according to an embodiment of the present invention has less backlash (backlash) of the rotary screw 200 compared to a conventional screw coupling, and thus can more precisely control the brake.

As shown in fig. 3, the piston 600 is disposed on the outer peripheral surface of the ball nut 400. Describing this in more detail, as shown in fig. 2 and 3, the piston 600 is formed in a cup shape having an opening portion 620 formed at a rear side. Thereby, the rotary screw 200 is inserted into the opening 620 so that the tip end portion can be disposed inside the piston 600.

Thereby, the piston 600 can move forward or backward with respect to the ball nut 400 in a state where the inner peripheral surface is in contact with the outer peripheral surface of the ball nut 400. Further, the outer circumferential surface of the ball nut 400 functions as a guide for guiding the movement of the piston 600.

At this time, when the rotary screw 200 disposed inside the piston 600 rotates, the ball nut 400 moves forward or backward according to the rotation direction of the rotary screw 200, and when the ball nut 400 moves forward, the front end surface of the ball nut 400 pushes the piston 600 so that the piston 600 moves forward.

At this time, an end of the piston 600 opposite to the side where the opening portion is formed, that is, a front end 610 of the piston 600 contacts the second brake pad 40, and when the rotary screw 200 further rotates, the piston 600 presses a rear surface of the second brake pad 40 so that the second brake pad 40 presses the brake disc 20. Thereby, a frictional force is generated between the brake disk 20 and the first brake pad 30 and the second brake pad 40.

At this time, as shown in fig. 4, the electromechanical brake 1 according to an embodiment of the present invention may further include a connection member 500.

When the rear surface of the second brake pad 40 is spaced apart from the front surface of the piston 600 as the first and

second brake pads

30 and 40 are worn due to friction with the brake disc 20, the connection member 500 moves the initial position of the piston 600 forward so that the front surface of the piston 600 can be in contact with the second brake pad 40.

Describing this in detail, as shown in fig. 4, the connection member 500 is formed in a cup shape such that the front end portion 420 of the ball nut 400 is surrounded, and the ball nut 400 is inserted into the opening side of the cup-shaped connection member 500. Thereby, as shown in fig. 4, the connection member 500 is disposed between the piston 600 and the ball nut 400.

With the addition of the connection member 500, the ball nut 400 does not press the inner front surface of the piston 600, as shown in fig. 4, pressing the connection member 500.

At this time, as shown in fig. 2 and 4, the connection member 500 may have a center portion of the front surface penetrated. However, in this case, the protrusion 520 protruding from the front inner circumferential surface of the connection member 500 is in contact with and supported by the front end portion 420 of the ball nut 400, whereby the connection member 500 can be moved forward by the ball nut 400.

At this time, as shown in fig. 4, a support surface 521 is circumferentially formed on the front inner circumferential surface of the connection member 500 such that a direction in which a load pressing the connection member 500 concentrates coincides with an extending direction of the second rotation shaft 341 when the ball nut 400 moves forward. Further, the ball nut 400 is formed with an inclined surface 421, and the inclined surface 421 corresponds to the support surface 521 of the coupling member 500 and is in close contact with the support surface 521.

In this way, the inclined surface 421 and the supporting surface 521 are formed to be inclined rearward from the surface perpendicular to the second rotation shaft 341, so that the net force of the ball nut 400 pressing the connection member 500 can be concentrated on the central portion.

As shown in fig. 4, a first screw part 540 is formed on the outer circumferential surface of the connection member 500. At this time, a second screw part 640 capable of being screw-coupled to the first screw part 540 is formed on the inner circumferential surface of the piston 600.

Accordingly, the connection member 500 is screwed to the piston 600 in a state of being disposed inside the piston 600, and at this time, the piston 600 can rotate in the direction of the second rotation shaft 341.

The piston 600 moves forward or backward according to a rotation direction of the piston 600, and a distance between the piston 600 and a rear surface of the second brake pad 40 may be adjusted.

As shown in fig. 5, the electromechanical brake 1 according to an embodiment of the present invention may further include a support member 270, an elastic member 280, and a thrust bearing 290.

As shown in fig. 2, the support member 270 is formed in a ring shape with a central portion thereof penetrating therethrough. At this time, as shown in fig. 5, the rotary screw 200 penetrates the support member 270, and the support member 270 is disposed in the third body portion 260 of the rotary screw 200. Thus, the outer peripheral surface of the third body portion 260 is disposed in contact with the inner peripheral surface of the penetrated central portion of the support member 270.

Accordingly, as shown in fig. 5, the support member 270 cannot move from the third body portion 260 to the first body portion 220 side due to the catch 222 formed at the rear side edge portion of the first body portion 220.

At this time, one side of the elastic member 280 is coupled to the support member 270. The other side of such an elastic member 280 is coupled to the ball nut 400.

The elastic member 280 serves as a tension spring, pulling the support member 270 to the front side, and pulling the ball nut 400 to the rear side. Thereby, even if there is some error in the ball screw nut coupling, the ball nut 400 maintains a state of being closely attached to the rear side, so that the braking can be accurately controlled.

As shown in fig. 5, the elastic member 280 may be configured to surround the outer circumferential surfaces of the ball nut 400 and the support member 270.

On the other hand, as shown in fig. 5, a thrust bearing 290 is disposed on the rear end surface of the support member 270.

When the brake disk 20 is pressed by the second brake pad 40 according to the rotation of the rotary screw 200, an axial force is generated at the rotary screw 200, so that the rotary screw 200 receives a backward load.

The thrust bearing 290 has a front surface contacting the support member 270 and a rear surface contacting a support portion formed inside the housing 50 to support the rotation screw 200 to which a load is applied. At this time, as shown in fig. 5, a separate member fixed inside the housing may be disposed at a rear side of the thrust bearing 290 so as to support a rear surface of the thrust bearing 290.

The electromechanical brake 1 according to an embodiment of the present invention includes a power transmitting portion 300.

The power transmission unit 300 is used to transmit the rotational driving force of the motor 100 to the rotary screw 200. To this end, the power transmission part 300 includes a first gear 320, a second gear 340, and a third gear 360.

At this time, as shown in fig. 6, the first gear 320 is coupled to the first rotation shaft 321 of the motor 100.

The second gear 340 is coupled with a second rotation shaft 341 of the rotation screw 200. The second gear 340 is fixed to the rear end of the rotary screw 200. At this time, the portion where the second gear 340 is provided is the second body portion 240 of the rotary screw 200.

As shown in fig. 6, the third gear 360 is disposed between the first gear 320 and the second gear 340 to be engaged with the first gear 320 and the second gear 340.

Thereby, the rotational driving force of the motor 100 is transmitted to the rotary screw 200 through the first gear 320, the third gear 360, and the second gear 340.

At this time, the kind of the gears is not limited as long as the first gear 320, the second gear 340, and the third gear 360 can transmit the rotational driving force from the first gear 320 to the second gear 340. In the present embodiment, as shown in fig. 6, the first gear 320, the second gear 340, and the third gear 360 are helical gears.

At this time, as shown in fig. 6, the third gear 360 rotates about a third rotation shaft 361 disposed apart from a plane including the first rotation shaft 321 and the second rotation shaft 341. To describe this in more detail, the first, second, and

third rotation shafts

321, 341, and 361 do not overlap but are spaced apart from and parallel to each other, and are disposed such that an angle (θ) formed by a straight line connecting a plane perpendicular to the first, second, and

third rotation shafts

321, 341, and 361 and a point at which the plane and the second and

third rotation shafts

341 and 361 intersect is a predetermined angle.

With such an arrangement structure of the first gear 320, the second gear 340, and the third gear 360, when the rotational driving force of the motor 100 is transmitted, a loss due to a repulsive force received by the third gear 360 can be reduced.

On the other hand, the planetary gear structure 800 connected to the rear end of the rotary screw 200 may be configured so as to adjust the rotational driving force transmitted to the rotary screw 200. At this time, one side of the planetary gear structure 800 is coupled to the rotary screw 200, and the other side is connected to the second gear 340. The planetary gear structure 800 is a known gear structure, and thus a detailed description thereof will be omitted.

The gear ratios of the first gear 320, the second gear 340, the third gear 360, and the planetary gear structure 800 described above may be variously designed according to the magnitude of the required braking force.

Fig. 7 is an enlarged view of a rotation preventing part of an electromechanical brake according to an embodiment of the present invention.

The electromechanical brake 1 according to an embodiment of the present invention may further include a rotation preventing part 700.

The rotation preventing part 700 serves to control the third gear 360 to rotate in only one direction.

A first space 721 is formed at one side of the third gear 360 such that the rotation preventing part 700 restricts the rotation of the third gear 360. The first space 721 may be formed at a front surface or a rear surface of the third gear 360. However, in the present embodiment, as shown in fig. 7, it is formed on the front surface of the third gear 360.

At this time, the latch 740 may be inserted into the first space 721. When the latch 740 is inserted into the first space 721, the third gear 360 is in a locked state capable of rotating only in one direction. Further, when the latch 740 is separated from the first space 721, the third gear 360 is in an unlocked state capable of bidirectional rotation.

For this, the first space 721 is circumferentially arranged around the third rotation shaft 361 on the front surface of the third gear 360. As shown in fig. 7, the first space 721 may be formed between a plurality of protrusions 720 protruding from the front surface of the third gear 360.

At this time, the protrusion 720 may have a guide surface 722 inclined to one side so that the latch 740 can rotate only in one direction in the inserted state.

On the other hand, the latch 740 may pivot inside the housing 50. Thus, one side of the latch 740 may be repeatedly inserted into the first space 721 or separated from the first space 721.

At this time, as shown in fig. 7, an actuator 760 is disposed inside the housing 50 to rotate the latch 740. Actuator 760 controls the rotation of latch 740.

At this point, actuator 760 may push or pull one side of latch 740 to cause latch 740 to rotate. For this, the actuator 760 may be a solenoid switch in which a permanent magnet 762 is disposed at a central portion of a coil wound a plurality of times, and the permanent magnet 762 may reciprocate by an electromagnetic force of the coil.

Thus, as shown in fig. 7, the front end of the permanent magnet 762 protrudes toward the latch 740 on the front side of the actuator 760. At this time, the side of the latch 740, to which the permanent magnet faces, is a metal on which a magnetic force can act, and can move according to the movement of the permanent magnet.

However, the manner of rotating the latch 740 is not limited thereto. For example, although not shown in the drawings, the latch 740 is hinge-coupled to a front end portion of the permanent magnet 762 so that the latch 740 can rotate according to the movement of the permanent magnet 762.

The actuator 760 is disposed adjacent to the motor 100, so that space efficiency inside the case 50 can be improved. Thereby, the size of the electromechanical brake 1 can be reduced.

Further, since the rotation preventing part 700 is installed at the gear adjacent to the motor 100, the power transmission part 300 may be prevented from being twisted in the locked state where the latch 740 supports the protrusion 720.

Hereinafter, the operation of the electromechanical brake 1 according to an embodiment of the present invention will be described in detail with reference to fig. 8 and 9.

Fig. 8 is a diagram illustrating a braking state of the electromechanical brake according to an embodiment of the present invention. Fig. 9 is a diagram illustrating a driving state of an electromechanical brake according to an embodiment of the present invention.

As shown in fig. 3 and 8, in a state where the electromechanical brake 1 presses the brake disc 20, the rotational driving force generated from the motor 100 is transmitted to the rotary screw 200 through the power transmission portion 300.

Thereby, the rotary screw 200 rotates and the ball nut 400 moves forward relative to the rotary screw 200. At this time, the connecting member 500 around the first body part 220 of the rotary screw 200 presses the piston 600, and presses the brake disc 20 through the second brake pad 40.

At this time, in order to maintain the braking state of pressing brake disk 20 as such, although not shown in fig. 8, latch 740 may be inserted into first space 721 by using actuator 760 to be converted into the locking state.

In contrast, as shown in fig. 9, when the pressing of the brake disk 20 is stopped and the vehicle is in a running state, the motor 100 transmits the rotational driving force in the opposite direction to the rotary screw 200 through the power transmission portion 300.

When the rotary screw 200 rotates in the opposite direction and the ball nut 400 moves backward with respect to the rotary screw 200, the piston 600 no longer presses the second brake pad 40. Thereby, the brake disk 20 can rotate without restriction.

Fig. 10 is a length-wise sectional view of a pair of a rotary screw and a piston of an electromechanical brake according to another embodiment of the present invention. Fig. 11 is an enlarged view of a power transmission portion of an electromechanical brake according to another embodiment of the present invention. Fig. 12 is an enlarged view of a load adjuster of an electromechanical brake according to another embodiment of the present invention. Fig. 13 is a view illustrating an operating state of a load adjuster of an electromechanical brake according to another embodiment of the present invention.

In the electromechanical brake 1 according to another embodiment of the present invention, a pair of pistons 600 and a pair of rotary screws 200 are provided. At this time, since the piston 600 and the rotary screw 200 are the same as the aforementioned piston 600 and rotary screw 200, a repetitive description thereof will be omitted.

The pair of pistons 600 and the pair of rotary screws 200 are disposed inside the housing 50 as shown in fig. 10. At this time, the shape of the housing 50 may be changed as needed, so that a pair of pistons 600 and a pair of rotary screws 200 may be arranged.

As shown in fig. 11, a pair of rotary screws 200 coupled with a pair of pistons 600 are connected to one motor 100 to receive a rotational driving force.

At this time, as shown in fig. 11, one third gear 360 is disposed between the first gear 320 coupled to the motor 100 and each second gear 340 coupled to the second body portions 240 of the pair of rotary screws 200.

At this time, the first gear 320, the second gear 340, and the third gear 360 are arranged such that an angle (θ) formed by a connecting line of the rotation center of the third gear 360 and the rotation center of the first gear 320, and a connecting line of the rotation center of the third gear 360 and the rotation center of the second gear 340 is a predetermined angle.

At this time, as shown in fig. 11, the pair of second gears 340 are symmetrically disposed at both sides of the first gear 320 and the third gear 360 and engaged with the third gear 360, so that each of the rotation screws 200 receives a uniform rotational driving force.

On the other hand, when the pair of pistons 600 presses the second brake pad 40, the pair of pistons 600 are symmetrically disposed on both sides of the center of the second brake pad with respect to the center of the second brake pad as shown in fig. 10 in order to use uniform load pressing.

When the second brake pad 40 is pressed by the pair of pistons 600, a stronger braking force may be provided, but if one piston 600 presses one side of the second brake pad 40 more strongly, wear may occur at one side of the second brake pad 40 first.

At this time, if the second brake pad 40 does not uniformly contact the brake disc 20 due to asymmetry, the frictional force is reduced, so that a problem of reduction of braking force may occur.

To this end, as shown in fig. 12, a load adjusting member 900 may be further provided at the electromechanical brake 1 according to another embodiment of the present invention.

The load adjusting member 900 applies a uniform load to a pair of the rotary screws 200 by pressing the rotary screws 200, which generate a small load when the brake disc 20 is pressed, toward the brake disc 20.

The load adjuster member 900 is rotatably installed between the pair of rotary screws 200 and the power transmission part 300. At this time, as shown in fig. 12, the load adjuster member 900 is formed to extend in length. The axis extending in the longitudinal direction of the load adjuster 900 is perpendicular to the pair of second rotating shafts 341.

A pin 930 is inserted through the center of the load adjuster 900. At this time, the pin 930 is disposed perpendicular to a plane formed by the pair of second rotating shafts 341. The pin 930 is fixed inside the housing 50.

As shown in fig. 10 and 12, both ends 910 of the load adjuster member 900 are formed as curved surfaces on the rotary screw 200 side. At this time, the curved surface formed at the load adjuster member 900 presses the rear surface of the support member 270 mounted to the third body portion 260 of the rotary screw 200 or the rear surface of the thrust bearing 290 disposed behind the support member 270.

As shown in fig. 12, a pair of through holes 920 are formed at both end portions of the load adjuster 900. The rear end portion of the rotary screw 200 penetrates each of the pair of through holes 920.

At this time, as shown in fig. 13, even if one piston 600 presses the second brake pad 40 due to one side of the brake pad being worn, the force with which the other piston 600 presses the second brake pad 40 is reduced.

At this time, one piston 600 receives a backward axial force, whereby the load adjuster member 900 rotates toward the other piston 600.

Thereby, when the end of the load adjuster member 900 on the other piston 600 side presses the other piston 600 side support member 270 or the thrust bearing 290, the other piston 600 can sufficiently press the second brake pad 40.

Therefore, even when one side of the brake pad is worn, the pair of pistons 600 can press the second brake pad 40 with a uniform load.

The electromechanical brake 1 according to various embodiments of the present invention has been described above. In this specification, a plurality of gear arrangements according to the present invention have been described for effectively transmitting a rotational driving force of a motor while pressing a brake disc using the motor, and increasing durability of internal components. Further, the present invention describes a structure capable of uniformly pressing the second brake pad by arranging a pair of pistons while using one motor. Further, an electromechanical brake is described which can perform the functions of a service brake and a parking brake by one motor even without a separate parking brake operating as a hydraulic line by having a rotation preventing part.

It is understood that it is obvious to those skilled in the art to which the present invention pertains that the electromechanical brake according to the present embodiment is applicable not only to a brake system of a vehicle but also to a brake for braking a rotating object.

As described above, the preferred embodiments according to the present invention have been described, and the fact that it is possible to embody in other specific forms than the above-described embodiments without departing from the spirit or scope of the present invention will be apparent to those of ordinary skill in the art. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the foregoing description, but may be modified within the scope of the appended claims along with their full scope of equivalents.

Claims

1. An electromechanical brake includes a pair of brake pads disposed on both sides of a brake disc, wherein,

the electromechanical brake includes:

a motor for providing a rotational driving force,

a rotary screw rotating about a second rotation axis parallel to the first rotation axis of the motor,

a power transmission unit for transmitting a rotational driving force of the motor to the rotary screw,

a piston coupled to the rotary screw in a manner capable of moving forward and backward so as to cause the brake pad to press the brake disc, and

a ball nut coupled to the rotary screw;

the power transmission unit includes:

a first gear coupled with the first rotation shaft of the motor,

a second gear coupled with the second rotation shaft of the rotation screw, an

A third gear that meshes with the first gear and the second gear and rotates about a third rotation axis disposed apart from a plane including the first rotation axis and the second rotation axis;

the rotary screw includes:

a first body part coupled to the ball nut,

a second main body part formed at the rear of the first main body part and coupled with the second gear, an

A third body portion formed between the first body portion and the second body portion;

the piston is formed in a cup shape having an opening portion at a rear portion thereof,

the ball nut is inserted into the opening of the piston to press the piston forward,

the first body portion, the third body portion, and the second body portion are formed such that the size of a cross section perpendicular to the longitudinal direction is sequentially reduced,

the electromechanical brake further comprises:

a support member disposed on an outer peripheral surface of the third main body portion, a front surface of the support member being supported on a rear end edge portion of the first main body portion, an

An elastic member having one side coupled with the support member and the other side coupled with the ball nut so as to pull the ball nut toward the support member side.

2. An electromechanical brake according to claim 1, further comprising:

a planetary gear structure, one side of which is coupled to a rear end of the rotary screw;

the second gear is coupled to the other side of the planetary gear structure.

3. An electromechanical brake according to claim 1,

the first gear, the second gear, and the third gear are helical gears.

4. An electromechanical brake according to claim 1, further comprising:

a connection member formed to surround a front end portion of the ball nut so as to be pressed forward by the ball nut, and having a first screw portion formed on an outer peripheral surface thereof;

a second screw portion that is screwed to the first screw portion is formed on an inner peripheral surface of the piston.

5. An electromechanical brake according to claim 4,

an inclined surface is formed on the front edge of the ball nut along the circumference,

a support surface corresponding to the inclined surface is formed at a front inner circumferential surface of the connection member to be pressed by the inclined surface.

6. An electromechanical brake according to claim 1,

the elastic member is formed in a spiral shape around the outer circumferential surfaces of the ball nut and the support member.

7. An electromechanical brake according to claim 6, further comprising:

and a thrust bearing disposed rearward of the support member to support a load generated by an axial force of the rotary screw.

8. An electromechanical brake according to claim 1, further comprising:

a rotation preventing portion that controls the third gear to be rotatable only in one direction.

9. An electromechanical brake according to claim 8,

the rotation preventing part includes a latch inserted into a first space formed at one side of the third gear,

the third gear is in a locked state capable of rotating only in one direction when the latch is inserted into the first space, and the third gear is in an unlocked state capable of rotating in both directions when the latch is separated from the first space.

10. An electromechanical brake according to claim 9,

the latch is fixed in a pivotable manner,

the rotation preventing portion further includes:

a plurality of protrusions formed continuously along a circumference of the third gear at one side of the third gear, an

An actuator for controlling pivoting of the latch;

a plurality of the first spaces are formed between the plurality of protrusions.

11. An electromechanical brake according to claim 10,

a guide surface formed obliquely is provided on one side of the plurality of protrusions in the circumferential direction of the third gear.

12. An electromechanical brake comprising a pair of brake pads disposed on either side of a brake disc, wherein,

the electromechanical brake includes:

a motor for providing a rotational driving force,

a pair of rotary screws that rotate about a pair of second rotary shafts parallel to the first rotary shaft of the motor, respectively, and are arranged side by side in a direction perpendicular to the direction in which the second rotary shafts extend,

a power transmission unit for transmitting a rotational driving force of the motor to the pair of rotary screws,

a pair of pistons coupled to the pair of rotary screws so as to be movable forward and backward so that the brake pads press the brake disc, and symmetrically disposed on both sides of the center of the brake pads with respect to the center of the brake pads, and

a load adjusting member that is rotatably provided between the pair of rotary screws and the power transmission portion, and applies a uniform load to the pair of rotary screws by pressing the rotary screws toward the brake disk, the rotary screws generating a small load when the brake disk is pressed;

the power transmission unit includes:

a first gear coupled with the first rotation shaft of the motor,

a second gear coupled with the second rotation shaft of the rotation screw, an

And a third gear that meshes with the first gear and the second gear and rotates about a third rotation axis that is disposed apart from a plane including the first rotation axis and the second rotation axis.

13. An electromechanical brake according to claim 12,

the load adjuster member is formed to extend in length,

both ends of the load adjusting member are formed into curved surfaces on the pair of the rotating screw rods.

14. An electromechanical brake according to claim 12, further comprising:

a ball nut coupled to the rotary screw;

the rotary screw includes:

a first body part coupled to the ball nut,

the first body portion, the second body portion, and the third body portion are formed such that the size of a cross section perpendicular to the longitudinal direction is sequentially reduced,

the electromechanical brake further comprises:

a support member that is disposed on an outer peripheral surface of the third main body portion and whose front surface is supported on a rear end edge portion of the first main body portion, an

A thrust bearing disposed rearward of the support member to support a load generated by an axial force of the rotary screw;

the load adjusting member presses a rear side of the thrust bearing.

15. A vehicle provided with an electromechanical brake, comprising:

an electro-mechanical brake according to claim 9,

a wheel having a brake disc coupled to one side thereof in such a manner that rotation axes thereof coincide, an

A pair of brake pads disposed on both sides of the brake disc and coupled to the electromechanical brake;

controlling a rotation speed of the wheel by pressing the brake disc with the brake pad while maintaining the unlocked state in a running state,

in a parking state, the brake disc is pressed by the brake pad while the locked state is maintained.